Currently, when a code division multiple access 2000 (CDMA2000) (a third generation (3G) mobile communications standard) network transits to a long term evolution (LTE) network, a voice solution simultaneous voice and LTE (SVLTE) becomes a preference of operators. The SVLTE is a technical solution that can resolve a voice transmission problem in an LTE network, and the solution makes it unnecessary for an operator to make too many modifications to a current network, which shortens an evolution period and reduces costs. A terminal with two modes being CDMA and LTE of a dual radio frequency system is introduced to the SVLTE, and the terminal uses two sets of radio frequency systems to separately process a CDMA20001x voice service and an LTE data service such that data and voice services can run at the same time.
For an SVLTE terminal that supports a CDMA2000 network and an LTE network, two sets of radio frequency circuits work simultaneously. In addition to bringing stress from the perspectives of power consumption, heat dissipation, layout, costs, and the like, a mutual interference problem between two signals of the radio frequency circuits also severely affects radio frequency receive sensitivity, thereby causing problems such as a network disconnection and call drop, and affecting normal use of a user.
Technical solutions for improving a signal interference problem in the prior art and respective disadvantages mainly include:
1. For antenna layout, a physical distance between an LTE antenna and a CDMA antenna is increased to the greatest extent, to decrease coupling between the two antennas. Generally, antenna isolation with a high frequency of 10 decibel (dB) and a low frequency of 8 dB can only be achieved by optimizing an antenna and increasing a physical distance between antennas, and an effect of improving a mutual interference problem is limited.
2. Interference to a received signal of a CDMA network is reduced in a manner of backing off transmit power of an LTE network and a CDMA1x (a first phase of CDMA2000) network, and more than 20 dB is backed off when necessary. Because transmit power at a network end is controlled by a network power control mechanism, and in principle, additional power backoff cannot be performed autonomously. Otherwise, a probability of call drop and network disconnection can be increased and user experience can be affected.